植物根际促生菌的分离及对桔梗的促生效应

Screening of Plant Growth-promoting Rhizobacteria and Their Growth-promoting Effects on Platycodon Grandiflorum

为了研究植物根际促生菌对桔梗的促生效应,并为克服桔梗连作障碍的促生菌剂研发提供优良的菌种资源,以溶磷和解钾能力为筛选指标,从商州区油菜根际土壤中分离了根际促生细菌,通过测定产氨、产IAA和固氮能力等多项指标对促生菌进行了筛选,进一步通过接种菌悬液的种子萌发试验测定了分离的菌株对桔梗幼苗生长的促生效应。结果表明,从油菜根际土壤中分离到19株同时具有溶磷和解钾能力的功能菌,其中6株菌(N-1、N-3、N-15、N-33、K-25、K-18)具备产氨、产IAA和固氮能力,3株菌(N-1、N-15、K-25)接种后的桔梗种子发芽率和幼苗茎长均明显高于未接菌的对照组,对桔梗有明显的促生作用,其中K-25菌株的促生效果最强。证明了从一种植物根际能分离到对另一种植物有促生作用的功能菌,促生菌在不同植物根际的分布和作用存在交叉现象。

To exploree the effects of plant growth-promoting rhizobacteria(PGPR)on Platycodon grandiflorum,and provide excellent strains for overcoming it's continuous cropping obstacles,using the ability of strains to dissolve phosphorus and release potassium as basic screening criteria,PGPR were isolated from the rhizosphere of Shangzhou Brassica campestris and the isolates were rescreened by several kinds of growthpromoting ability as screening criteria,and through the test of seed germination inoculated with bacterial suspension the growth-promoting effects of PGPR on Platycodon grandiflorum were deternubed.The result showed that19strains of bacteria were isolated from the rhizosphere soil of Shangzhou Brassica campestris along with the ability to dissolve phosphorus and release potassium,in which6strains(N-1,N-3,N-15,N-33,K-25,K-18)have the ability of producing ammonia,IAA and nitrogen fixation.The germination rate and seedling stem length inoculated with bacterial suspension of N-1,N-15and K-25were significantly higher than those in the control group,in which the strains K-25,N-1and N-15have significant growth-promoting effect on Platycodon grandiflorum,.and the growth-promoting effect of strain K-25is the strongest..It proved that the PGPR can be isolated from the rhizosphere of one plant that have growth-promoting effect on the other.The distribution of PGPR exist cross-distributed phenomenon in different plant rhizosphere.